Efficient electrochemical generation of active chlorine to mediate urea and ammonia oxidation in a hierarchically porous-Ru/RuO2-based flow reactor
File(s)
Accepted version
Supporting information
Author(s)
Zhang, Kai
Duan, Yuanxiao
Graham, Nigel
Yu, Wenzheng
Type
Journal Article
Abstract
The electrochemical chlorination of urea to CO2 and N2 end-products, via active-chlorine-mediated oxidation under nearly neutral conditions, is an effective treatment for medium-concentrated urea-containing wastewater. Herein, we design a novel flow reactor integrated with three-dimensional hierarchically porous Ru/RuO2 architectures anchored on a Ti mesh. The hierarchically macroporous electrode can create sufficient exposure of catalytically active sites and facilitate the microscopic mass transport and diffusion inside the active layer, thereby contributing to the increased removal efficiency of urea-N and ammonia-N. The combined results of electrochemical measurements, UV–visible spectrometry and in situ Raman spectrometry, show that the OCl- species produced by chlorine evolution reaction (CER) are the main active constituents for removing urea-N. Theoretical calculations reveal thLTWAat the Ru/RuO2 possesses a moderate Cl binding strength, lower theoretical overpotentials of CER and a higher conductivity, compared with pure RuO2. On this basis, we assemble a circular flow reactor with the hierarchically porous electrodes in a two-electrode system to obtain an enhanced microfluidic process, which during 9 days of uninterrupted operation, at a high electrolysis current of 500 mA, achieve a total nitrogen removal of 92.6% and an energy consumption of 7.94 kWh kg−1 N, demonstrating the promising application of the novel process.
Date Issued
2023-02-15
Date Acceptance
2022-11-03
Citation
Journal of Hazardous Materials, 2023, 444 (Part A)
ISSN
0304-3894
Publisher
Elsevier
Journal / Book Title
Journal of Hazardous Materials
Volume
444
Issue
Part A
Copyright Statement
Copyright © Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/
License URL
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000903477600002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
Circular flow reactor
Electrocatalysis
Electrochemical chlorination of urea
Engineering
Engineering, Environmental
Environmental Sciences
Environmental Sciences & Ecology
EVOLUTION REACTION
Hierarchically porous channels
Life Sciences & Biomedicine
RECOVERY
Ru
RuO 2 electrode
Science & Technology
SOURCE-SEPARATED URINE
Technology
WASTE
WATER
Publication Status
Published
Article Number
130327
Date Publish Online
2022-11-04